1. Field of the Invention
The present invention relates to a front light module, especially to a front light module capable of improving display quality.
2. Description of the Related Art
Front light modules for transflective or reflective displays are commonly of edge-lighting type or direct-lighting type, wherein the front light modules of edge-lighting type are becoming dominant due to the market's growing demand of small form factor on displays.
Prior art front light modules of edge-lighting type generally install a downward-light-guiding means on the top face of a light guide plate, to transform an edge light to a uniform plane light, which emits light beams downward to provide illumination for a display. Please refer to FIG. 1, which illustrates a sectional view of a prior art front light module for providing a plane light to illuminate a reflective type LCD 140. As illustrated in FIG. 1, the prior art front light module includes a light source 100, a reflective cover 110, a diffusion plate 120, and a light guide plate 130.
In the module, the light source 100, reflective cover 110, and diffusion plate 120 are used for providing diffused incident light.
The light guide plate 130, of which the left side face is a light entrance surface neighboring the diffusion plate 120, and the bottom face is a light exit surface, has a plurality of diffusion points 131 on the top face, wherein, the diffused incident light hitting the diffusion points 131 indirectly (after going through a total reflection at the bottom face of the light guide plate 130) or directly will be scattered off, and some of the scattered light—of which the traveling direction forms with the normal of the light exit surface an angle smaller than a total reflection angle—will pass through the light exit surface to illuminate the reflective type LCD 140.
There is another prior art design using microstructures as a means for guiding light downward. Please refer to FIG. 2, which illustrates a sectional view of another prior art front light module for providing a plane light to illuminate a reflective type LCD 240. As illustrated in FIG. 2, the prior art front light module includes a light source 200, a reflective cover 210, a diffusion plate 220, and a light guide plate 230.
In the module, the light source 200, reflective cover 210, and diffusion plate 220 are used for providing diffused incident light.
The light guide plate 230, of which the left side face is a light entrance surface neighboring the diffusion plate 220, and the bottom face is a light exit surface, has a plurality of V type microstructures 231 on the top face, wherein, the diffused incident light hitting the V type microstructures 231 indirectly (after going through a total reflection at the bottom face of the light guide plate 230) or directly will be reflected to travel down along the normal of the light exit surface to pass through the light exit surface to illuminate the reflective type LCD 240.
However, as the diffusion points 131 of the prior art front light module of FIG. 1 and the V type microstructures 231 of the prior art front light module of FIG. 2 are located at the top face of the light guide plate, therefore they both have the problem of being subject to getting scratched, which will degrade display quality, and even make the front light modules disqualified.
In view of the foregoing problem, the present invention proposes a front light module having a novel structure for guiding light downward.